1.1 本规范涵盖碳钢梁轨道 2. 根据类型或类型和重量，以及化学定义如下和 表1 . 1.1.1 除非买方另有规定，否则主梁护栏应为A级。 1.1.2 重量低于135磅/码（67.1千克/米）的平梁和槽梁轨道应由买方指定为A类或B类。 1.1.3 除非另有规定，否则重量大于等于135磅/码的平梁和槽梁轨道应为C级。 1.2 以英寸-磅为单位的数值应视为标准值。括号中给出的值是到国际单位制的数学转换，仅供参考，不被视为标准值。 1.3 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。

1.1 This specification covers carbon steel girder rails 2 of three classes based on type or type and weight, and chemistry defined as follows and in Table 1 . 1.1.1 Unless otherwise specified by the purchaser, girder-guard rails shall be Class A. 1.1.2 Plain and grooved-girder rails under 135 lb/yd (67.1 kg/m) in weight shall be specified by the purchaser as either Class A or Class B. 1.1.3 Plain and grooved-girder rails of 135 lb/yd in weight and heavier shall be Class C, unless otherwise specified. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.